File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

CPL file extension

Windows Control Panel Item

System Files

CSV file extension

Comma Separated Values File

Data Files

CUR file extension

Windows Cursor

System Files

DEB file extension

Debian Software Package

Compressed Files

DRV file extension

Device Driver

System Files

HTM file extension

Hypertext Markup Language File

Web Files

IBOOKS file extension

Multi-Touch iBook

Data Files

JPG file extension

JPEG Image

Raster Image Files

PART file extension

Partially Downloaded File

Misc Files

PKG file extension

Mac OS X Installer Package

Compressed Files

PS file extension

PostScript File

Vector Image Files

PSPIMAGE file extension

PaintShop Pro Image

Raster Image Files

VB file extension

VBScript File

Executable Files

WPD file extension

WordPerfect Document

Text Files

WSF file extension

Windows Script File

Executable Files